1. Field of the Invention
This invention relates to the field of RADAR simulation devices and more particularly to visual RADAR displays.
2. Description of the Related Art
This invention relates generally to simulation graphics and more particularly to a method and a system for simulation of a display of raw RADAR data.
Visual Radar displays are well known. From the time of the first RADAR to the present state of the art, it has been essential that the output of RADAR antenna signals be capable of human interpretation. Screens that have illumination properties, such as oscilloscopes, have long been used to display the processed antenna signals and to provide the visual man-machine interface. Today these screens include many models of cathode ray tubes, plasma displays and other well-known visual screens that receive and display electronic signals.
The benefits of RADAR technology have been experienced in multiple environments and now RADAR is used in a multitude of applications. For example, RADAR is used at airports to coordinate aircraft. It is used on aircraft, ships, shore installations and space vehicles to locate objects and calculate their location and velocity vectors. It is used to identify and track weather. It has provided a tool to map the moon and obtain information on the atmosphere of Venus. The uses are many and ever increasing.
In the early days of the art, the signals received by a RADAR receiver were processed with analog technology. Recently, digital technology has been applied to the signal processing of incoming RADAR signals. The properties of analog signals are different from the properties of digital signals resulting in differences in the production of RADAR data for display.
When the RADAR receiver receives the RADAR antenna signals, the incoming RADAR antenna signals receive additional digital processing for two purposes. First, if the incoming RADAR signal is only processed for the purpose of providing a compatible display on a visual display such as an oscilloscope, the processed signal is known as a “raw” signal: The “raw” signal is therefore only processed for interface with the output device but not for machine interpretation. Second, enhanced signal processing can be applied to the incoming RADAR signal for the purpose of providing computer assisted interpretation. The display of enhanced signal processing consists of machine-interpreted objects depicted by a combination of shapes such as triangles, squares and arrows with additional alphanumeric display data.
The need for training qualified RADAR operators, who provide the human half of the man-machine interface has expanded along with the uses of RADAR technology. One of the goals in training operators includes reliable interpretation of the RADAR data as decisions, sometimes-critical decisions, must quickly be made upon the presentation of data.
In training RADAR operators the fidelity of the simulation is very important, especially when raw RADAR data is being simulated. In particular, “fade” is a characteristic of the RADAR display. “Fade” is the gradual disappearance of the image produced during sweeps of the RADAR over one or more information captures cycles. Fade is important in differentiating new data presented on the display from previous data on the display to present a dynamic representation of changes that are occurring in the environment depicted on the RADAR screen. Thus, the fidelity and conformity of the fade in the simulated RADAR display is directly correlated to the performance of the RADAR operator in the actual operating environment.
Raw RADAR software simulations utilize digital processing that incorporates palette swapping and other software techniques to perform a fade. For example, U.S. Pat. No. 4,944,679 discloses RADAR display screen phosphor decay by reducing color intensity on a color lookup table over time. These techniques typically result in a segmented, choppy, or uneven picture. Thus, existing RADAR simulations provide emulation of RADAR video, but there is a need to improve the emulation of RADAR video, and in particular raw RADAR video.